From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-18.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 0519DC433E9 for ; Mon, 28 Dec 2020 14:23:42 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id C665F22B3B for ; Mon, 28 Dec 2020 14:23:41 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2502818AbgL1OXf (ORCPT ); Mon, 28 Dec 2020 09:23:35 -0500 Received: from mail.kernel.org ([198.145.29.99]:56064 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2437893AbgL1OVA (ORCPT ); Mon, 28 Dec 2020 09:21:00 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id 6281E22B2E; Mon, 28 Dec 2020 14:20:44 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1609165245; bh=5zn/4xyB1eu5gYq4y6UvWcr7Apf3HUkruUXsWMQBIZo=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=VSRUstEipRUM6ql2dMRS4XkScUJEjardLrBqG6j31oPXRSJrSMWS7gKccVrOHS83/ NZFy+mVLO+UTg7BJu5qyTcuWORpsLTPhosfc1V/QAziMRP8/+dAMiyWNyXHr09gyZs +aVBdUXLKAsL4y1PJD9rSWE1ldpTMz4MJKkUobek= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, =?UTF-8?q?Bj=C3=B6rn=20T=C3=B6pel?= , Jakub Kicinski , Sasha Levin Subject: [PATCH 5.10 463/717] i40e, xsk: clear the status bits for the next_to_use descriptor Date: Mon, 28 Dec 2020 13:47:41 +0100 Message-Id: <20201228125043.154251286@linuxfoundation.org> X-Mailer: git-send-email 2.29.2 In-Reply-To: <20201228125020.963311703@linuxfoundation.org> References: <20201228125020.963311703@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Björn Töpel [ Upstream commit 64050b5b8706d304ba647591b06e1eddc55e8bd9 ] On the Rx side, the next_to_use index points to the next item in the HW ring to be refilled/allocated, and next_to_clean points to the next item to potentially be processed. When the HW Rx ring is fully refilled, i.e. no packets has been processed, the next_to_use will be next_to_clean - 1. When the ring is fully processed next_to_clean will be equal to next_to_use. The latter case is where a bug is triggered. If the next_to_use bits are not cleared, and the "fully processed" state is entered, a stale descriptor can be processed. The skb-path correctly clear the status bit for the next_to_use descriptor, but the AF_XDP zero-copy path did not do that. This change adds the status bits clearing of the next_to_use descriptor. Fixes: 3b4f0b66c2b3 ("i40e, xsk: Migrate to new MEM_TYPE_XSK_BUFF_POOL") Signed-off-by: Björn Töpel Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin --- drivers/net/ethernet/intel/i40e/i40e_xsk.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/drivers/net/ethernet/intel/i40e/i40e_xsk.c b/drivers/net/ethernet/intel/i40e/i40e_xsk.c index 567fd67e900ef..e402c62eb3137 100644 --- a/drivers/net/ethernet/intel/i40e/i40e_xsk.c +++ b/drivers/net/ethernet/intel/i40e/i40e_xsk.c @@ -219,8 +219,11 @@ bool i40e_alloc_rx_buffers_zc(struct i40e_ring *rx_ring, u16 count) } while (count); no_buffers: - if (rx_ring->next_to_use != ntu) + if (rx_ring->next_to_use != ntu) { + /* clear the status bits for the next_to_use descriptor */ + rx_desc->wb.qword1.status_error_len = 0; i40e_release_rx_desc(rx_ring, ntu); + } return ok; } -- 2.27.0